Just as an aside I had a real issue with this card today. Added a backup account (Santander) as requested and then my entire account was frozen for “commercial reasons” and I was being led to believe the account was being closed down.

I had to unlink the Santander account and call them to get them to unfreeze my account.

It’s an odd one, given it’s an older and more used account than the one I had linked as my main (Monzo) but apparently they run “commercially sensitive” reviews for any accounts being linked.